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AM on FM

Back in the early days of FM, when AM radio ruled the roost and an FM radio was still a rare commodity, many station owners simply simulcast their AM station’s programming on their FM stations. In the 1960s the Federal Communications Commission put the kibosh on that scheme, ordering FM stations to air different programming. This, in turn led to the development of freeform FM radio, since many station owners were glad just to have something to put on air that didn’t cost them much money. However, by the early 70s the increased fidelity of FM would make that band profitable in its own right, overtaking AM in audience share by the 80s.

Colorado Dept. Transportation radio network with repeater stations

Colorado Dept. Transportation radio network with repeater stations

Yesterday the FCC took us back to the future, in a way, approving the use of FM translator stations by AM stations (PDF of Report & Order). Translator stations are repeaters for full-power stations intended to fill in gaps in its signal area that might exist due to geography or other propagation anomalies. By design translator stations are low powered at anywhere from 10 to 1000 watts and may not originate their own programming. They’re also allowed to be short-spaced on the dial, crammed into channel spaces closer than permitted for full-power stations, or LPFM stations (for more on that discrepancy see this post from Matthew).

When the idea of AM stations having FM translators was first proposed I was quite skeptical, fearing an onslaught of new translators repeating commercial AM programming filling up every available nook and cranny on the FM dial, pre-empting the further expansion of LPFM. Luckily the actual order passed by the FCC is more rational than feared.

As the Broadcast Law blog points out, AM stations will only be permitted to make use of FM translators already licensed or issued a construction permit as of May 1, 2009. That means there won’t be a land grab brought on by a rush of new translators–station owners will have to rely on the translators they’ve already been granted by the FCC. It also means stations owners will have to make a choice as to whether their FM translators will be more valuable repeating an FM property or AM.

The NAB lobbied for AM repeaters on FM in order to compensate for two situations. First, the overly crowded AM dial is often useless at night (and I wonder who’s to blame for that?) due to interfering signals brought on by the ability of AM signals to propagate further after dark. The second is that many AM stations still have day-time only licenses, since they would cause too much interference after dark.

I’m still skeptical of the need for AM stations to have translators on the FM dial, since any broadcast group large enough to have licenses for FM translators already has FM properties it could switch its AM stations over to. This change isn’t going to help any of the few remaining independently owned AM stations not accompanied by any FM licenses. So it just sounds like the big commercial broadcasters want to have their cake and eat it too.

I’m just glad there isn’t a new translator license application window scheduled so that there might still be some frequencies available for low-power FM in the near future.


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